Guideline-practice gap in the management of predialysis chronic kidney disease mineral bone disorder in Japan.

No study has reported the current status of the management of chronic kidney disease mineral bone disorder (CKD-MBD) in Japan. Using the Osaka Vitamin D Study in CKD (OVIDS-CKD), we examined the prevalence of patients with serum calcium, phosphate, parathyroid hormone (PTH), or 25-hydroxyvitamin D levels outside the target of KDOQI guidelines. Eighty-four percent of the patients had 25-hydroxyvitamin D <30 ng/mL. Significant determinants of poor vitamin D status were female gender, diabetes, high PTH, and high urinary protein (2+ or greater). The percentage of patients with intact PTH higher than the target was 8% in CKD stage 3a, while between 20-22% in stages 3b to 5. The patients indicated for ergocalciferol were 7, 18, and 19% in stages 3a, 3b, and 4, respectively, and those indicated for active vitamin D were 21% in stage 5. Since neither ergocalciferol nor cholecalciferol is available in 2011 in Japan, we have no choice but to prescribe alfacalcidol or calcitriol; however, the percent of patients receiving these drugs was only 1, 4, 8, and 14% in stages 3a, 3b, 4, and 5, respectively, indicating that PTH and vitamin D status are not well controlled in Japan. In contrast, more than 80% of the patients met the target of serum calcium and phosphate. Contrary to expectations, nearly 20% of the patients had hypophosphatemia in stage 3 and 5, possibly because of strict protein restriction. Given these results, nephrologists should consider prescribing active vitamin D, especially for females and patients with diabetes, massive proteinuria, or secondary hyperparathyroidism.